fix(ffi): preserve dictionary ordered flag when importing FFI schema

[fuleinist]

Summary

When converting an FFI_ArrowSchema (C Data Interface) into a Field, the
dictionary ordered flag is silently dropped. FFI_ArrowSchema::dictionary_ordered()
reads the ARROW_FLAG_DICTIONARY_ORDERED bit (0b1) from ArrowSchema.flags
correctly — but impl TryFrom<&FFI_ArrowSchema> for Field never applies it to the
resulting Field.

As a result, a dictionary field exported with dict_is_ordered = true always comes
back as dict_is_ordered = false after an FFI round trip.

Fix

One-line change: call .with_dict_is_ordered(c_schema.dictionary_ordered()) when
constructing the Field in the TryFrom<&FFI_ArrowSchema> impl.

// Before
let mut field = Field::new(c_schema.name().unwrap_or(""), dtype, c_schema.nullable());

// After
let mut field = Field::new(c_schema.name().unwrap_or(""), dtype, c_schema.nullable())
    .with_dict_is_ordered(c_schema.dictionary_ordered());

with_dict_is_ordered is a no-op on non-dictionary types, so this is safe for all
schema types.

Test

Adds test_dictionary_ordered_roundtrip that verifies both the ordered and
unordered paths survive an export/import round trip through the C Data Interface.

Fixes #10513

[Jefffrey]

thanks for the submission, but we have an existing PR for this

• fix(arrow-schema): Persist dictionary ordered flag on FFI schema import #10514